Hello @Tentha.
Over at GilletteClan we are doing the exact same thing but for CoD4 then porting it over to MW2 & MW3. Currently we have a complete remaster of Rust coming out in the next few days. We also have Hardhat, Pipeline and Grind coming too. We're making a DLC pack for our infected servers, its pretty cool.
If you ever wanted to chill in voice chats with us we normally work on them daily, at the same time we can give you some ideas on zombie maps. Personally I am a massive zombie fan and I can already some up with a thousand ideas.
At the same time if you're ever interested we could host your maps on a T4 & T5 server but we can talk about that at a later date.
If you wanted to see what we're up too add me on Discord: Stix#0001
Im very excited to see what you come up with!