so... in the end.. ty bombguy! While dealers cannot get the clamps from BMW they do (at least Sonnen BMW does) get them in bags of 100 from elsewhere, and were willing to sell me a few at 1.50 each. Picked up Oetiker clamp pliers (Knipex 1099i) on eBay (usually between 20 and 26 shipped.) I've also read that you can use regular end nippers to clamp - if you grind down the cutting edges; but the Knipex also have a side clamping ability that would work well in tight places.
The clamps available at Kragen/Autozone, being universal, didn't seem to have a good enough tightening mechanism - they may work, but...
eEuroparts sells boot clamps that look similar to OEM (50.2060.1) and they also sell a more more substantial clamp plier (4210) - at $23.90 w/o shipping.
With the CV joint grease repacked, and clamped - looking forward to see if I solved my xi vibration problem - but to find out have to drive a few hundred miles and then hit the mountains on afreeway.