A few of my PCs have died. It happens. But now what? Specifically, now what happens to their items? They are rolling up some new characters and I assume they should follow the character wealth guidelines for their current level, but what is stopping them from locating their corpses and effectively doubling their wealth just like that? How do you deal with dead characters' wealth?
I see several options here:
Get over it
Talk about it
Most likely you will have to implement several of these methods to come up with a true solution, but here are my recommendations for each:
Get Over It As a player (but more a GM) you're putting yourself out there a bit. Yes it'd be nice if your players respected your NPCs a bit more, but if you are enjoying the game why is it a big deal? You may need to examine your expectations here. Maybe your group is looking for a lighter play style than you are.
Embrace It Pun it up, make your NPCs fit their puns. Make your ridiculous character all the more ridiculous. This may not work if you're looking at a more serious play style, but even those have room for humor. Or maybe your Minotaur has a complex...Maybe it's no metagaming, maybe it's really an insult. Maybe your character really is a cow?
Talk about it This is the hardest of my recommendations, but is probably the most useful. Most likely your group doesn't see an issue. You've got to actually dialogue about how your expectations are different from what plays out at the table and talk about how you guys can come to a solution. This is cooperative gaming, it should also be about cooperating to have a good time so everyone can have fun. This is especially important if you feel offended or if the jokes have crossed the line. There is no reason to sit and stew when if you asked them to stop they would likely stop.
Change it Come up with a different character concept, do a better job roleplaying/naming/characterizing your NPCs. This isn't to say that you're not doing fine right now, just that if it's bothering you, use it as motivation to get better.
It sounds to me like your expectations and your groups' expectations are kind of on a different page. Really most of this boils down to aligning those and continuing on. If you're group is looking for beer and peanuts to relax after work and you're looking for serious theater, you might have to all adjust your expectations and find different outlets for the sentiments that are no longer welcome at the table.
Personally I think it's important to have fun at the gaming table and if something is impinging on your fun you should let your group know. I'm pretty sure they'd be happy to help you fix it, even if it means they have to pass on the cow jokes.
I used to play The Dark Eye (Das Schwarze Auge) myself and in my opinion it strongly resembles medieval Europe - apart from the obvious fantasy additions. It's rule books give information of the economy, trade and demography of nearly everything.
Therefore the dilemma is quite understandable; in medieval Europe a sword was worth a fortune and in the world of The Dark Eye it is the same. However, a hero needs a sword right?
Well, maybe not necessarily. In our group we don't have a rule to handle wealth but here are some thoughts on how we somehow deal with it usually (after writing it down I realised that our heroes are not that wealthy because of these guidelines so it may not suit your question that well):
Equipment has flaws. Nearly everything a (starting) character possesses is not a shiny new blade but rather a crude axe, and old dagger from the grandpa, a warm winter coat with some holes, the elven bow that was handed to the character in a ceremony and would not be considered for sale.
Producing goods has its cost. It is true that potions or magical items are worth a hell lot of money in The Dark Eye. But producing these is an investment and requires material and knowledge - both of which can be costly to find.
Valuable findings are rare. Again, nearly everything a character finds, loots or gets possession of has either flaws or is an unknown object that requires identification. However, here you'll find yourself in a situation where player and character knowledge interferes. An adventurer may not have ever seen a telescope and finds no use in keeping it but the player knows it is worth a ton of money. We also have some problems with stealing because the players have knowledge about the worth of goods - also stealing creates a difficult situation by either letting it pass or punishing the character that may hinder adventure progress (but that's a different story).
Carrying gold or whatever currency is not very common. Carry a chest full of gold and silver and it will attract thieves. Taxes may be imposed upon crossing borders and cities. And the greedy tavern keeper will charge more if he spots the characters entering in bling bling.
Value comfortable but rule-speaking unnecessary goods. Create an environment where player not only value the next best weapon or armor because it will raise their damage and defence in battle. Good shoes can be expensive but keep from getting exhausted and have a minor impact on game balance. The same with regular feel-good massages, company during the night, the feast at the end of an adventure. The more characters act with each other and the more a personality they have the more readily the spend money on that. All these are sorts of money sinks.
But in the end the characters are heroes and it may be frustrating to not get a bit wealthy at some point. The reward for risking their life is loot, treasure and occasionally - a very special event - the acquisition of a new and shiny sword.