Lecrae is good.
Early TFK (Thousand Foot Krutch) is good, like, way early TFK- Set It Off, That's What People Do, Shutterbug, though they have a lot of rock and metal influences- they're still rap though, but more like Linkin Park raps (only perhaps a tad more upbeat), I'd recommend When In Doubt as an amazing song, specifically, and Trevor (TFK's singer, best Christian rapper) performs on a few odd tracks like Run For Cover by KJ-52, Skills by Manafest, Impossibly by Manafest and...I think it was Kick It? also by Manafest and then another KJ song- I forget which. Manafest is another Christian rapper, so's KJ-52. tobyMac has some rap songs like Irene, Lose My Soul, Face of the Earth, Burn For You, etc. and the whole Momentum album is kinda like early TFK- except its more of an industrial rock fusion instead of a rap/metal fusion. Actually, think LP's Hybrid Theory with a heavier influence on the rap side. Family Force 5 has all fast electronic dance beats to it- but their first album is solidly rap. Actually, its really industrial rock/rap fusion. Business Up Front, Party In The Back is the name.
Hope that helps.