Jake
That's very interesting you have a XL7. I know they were sold over in Europe but never have I seen one here until now. Also it's interesting you have a XL Legend that's in the same black color as the XL21/XL7. I've read they were only sold in red and blue unless the blue ones are mislead as black or there are also in fact blue ones and I haven't seen one yet, I've already seen the red ones. But I do have a XL Platinum that's blue, I think the blue ones were more popular than the red ones.
Anyways regarding the XL 9100, awesome find! They're one of my favorite Orecks. I like the ones that has the switch on the base more than on the handle, it's just more simpler and the pistol grip handle feels better on my hands.