There are people who do this stuff for free - try some local gaming forums or something. I do it all the time with my Pandora for others.
Making a Pandora doesn't have to be cutting it open, there's a completely safe and reversible software method, as long as you have one PSP with CFW prepared. It's a win-win situation.
Don't give up, I'm sure you'll find someone!

Software modding a battery? Do you happen to have a link?

Here ya go.

This is an older guide... The easiest way is using Despertar Del Cementario v8.
EDIT: HOWEVER, I do not know if Pandora is applicable to all 3k models. That's something you'll have to experiment with if you want to...

Both of those require a psp with custom firmware which is the objective of the whole exercise

...And you really can't mod a PSP today without another one already modded. It was one thing in the beginning when anyone with firmwares up to 3.50 could simply install CFW, but now you need to really go all out. Gotta give it to Sony, they are really making it harder for us. :/

Yeah thats what the guys over at pspslimhacks were saying, even the pandora method is unreliable or impossible with the newer hardware. Decided I might as well upgrade to the latest firmware and call it a day. If a hack comes out one day then I'll give it a bash but if not I'll just use it as is