Bravada vibration at 2100 rpm

My 98' Bravada vibrates terribly when I'm decelerating right around 2100 r's, and vibrates pretty regularly (if vibrations can be regular) when I'm pulling out and when I'm going between 40 and 65. I don't really think it's the wheel bearings, both of em were replaced about 4 months ago.
Anyone have any idea what it could be?

Sounds like bad universal joints on the rear driveshaft. After taking it off, the joints should freely wobble the full range of movement...no tight spots before contacting the joint/driveshaft end or the transmission yoke/driveshaft other end. Orange rust on the u-joint seals are a pretty good indicater too.
My Dodge hadda tight spot before achieving full movement on the transmission yoke/front end then the vibration dissapeared upon u-joint replacement.
The same applies to the front drive shaft and even the front wheel constant velocity joints if the vibration is felt stronger in the steering wheel than in the seat or floor.

Ya know what, it probably wouldn't hurt to check the lug nuts on the wheels first.

Yeah that was what I was thinking... for all I know my rear driveshaft could be loose.

Anyhoo, if I'm looking for a replacement, where's the best place to get one?

Just pill the driveshaft out and take it to a machine shop (some NAPAs have them) and get 2 u-joints installed and call around cause I always get it balanced too - tack weld a weight on for high speed. About $100 for the work if you pull. You can save $20 doing it yourself but no balance then.
Also the Bravada AWD has transfer case issues due to the clutches in the case so change that fluid with GM blue Autotrak syn fluid and that vibration has a bulletin on it so search the posts. Check the front and rear diff fluids also. Bad CV axles can also cause it. Lower ball joints been done yet.