That's a cool idea. Would you be incorporating anything else (spear/shoufa sounds kinda cool to me). As far as the pain goes, it really depends on where you get the tattoo. I've got 4, two that are 1/2 sleeves (upper arms), one on my chest and one on my forearm. The forearm hurt the least, but the bicep part of the arm was also pretty much painless. It's more of a an annoyance (especially the buzzing). If you're not going with super huge than you'll go numb pretty quick and likely be done with it before it goes to the other side. If you're going to go larger, and you don't have a lot of pain tolerance you can break it in to smaller chunks so it's not as bad. I did both 1/2 sleeves in one sitting and my arms were on fire by the end of it. That was about 8 hours each.
The best advice I can give for getting past the pain part is to bring a friend along who is a chatty person. On some of the more painful parts having someone talking to you about something that will engage you in the conversation (you really need to think about responses and respond, not just listen to them) can make you pretty much forget about what's going on.
Before doing the tattoo make sure you research the artist and see what kind of work they have done, and what they specialize in. You don't want to wind up with something that looks like crap. Also don't skimp on price. If they only charge $50 for a tattoo that takes 2 hours and covers your forearm then I'd be scared. Location matters when doing the price as if it's a tough place to tattoo (ie ribs, lip, face) they will charge a lot more. So if you're putting a nice piece that goes from wrist to elbow you can expect to spend $200+ from a reasonably good artist.
If you're in the northwest I'd be happy to hook you up with the guy who did mine. He's really reasonable on price, and does exceptional work (you can see one sleeve in the earlier post). My wife has 2 and is getting a 3rd from him, I've got the two sleeves. Be happy to share some pictures.