I have one, the William Optics DCL-4337 that allows me to screw straight into my camcorder and do videoscoping. Very nice.
Some other eyepieces that I have that videoscope well are the Pentax XW20 (but not the others, haven't tried the XW30 since it's a 2"), Scopetronix Maxview14, and Siebert Performance 35.
For no vignette videoscoping without turning the zoom up all the way, I've found the Panasonic HD camcorders to be the best because they allow you to take off the front threads and lens cover thus allowing the eye lens to sit closer to the camcorder lens.
For my Siebert Ultra eyepieces, I've found that they work better in my astro scopes than they do in my Pentax spotter. Apparently after I OCA them for binoviewing, the view becomes delightfully razor sharp. On the Pentax, they are a tad softer.
Sadly for you, I find the very best 20mm eyepiece is still the Pentax XW20. My Siebert Ultra 24mm, Edumund RKE 21mm, Siebert Ultra 17mm along with the rest of the cheaper eyepieces I've reviewed last time all lose to it. The closest cheaper alternative for you maybe the Siebert Performance 25mm if you don't mind the fully coated coatings and narrower 55 degree fov; that's the same eyepiece that go into the Siebert QMod binos. I've also read good things about the Hyperion 21mm though I've never tested it.
Another one worthy of consideration maybe the Orion Edge-On 19mm eyepiece with 65 degree fov and 17m eyerelief; it is well coated and constructed with a nice view. The barrel on the 27mm version that I tested was a tad narrow for the Pentax spotter to lock it in place. One would have to wrap the barrel with black electrical tape to widen its barrel's outer diameter enough so the Pentax spotter can secure it. I sent the 27mm back simply because the magnification wasn't significantly different enough from my XW20 and Siebert Ultra 24's.
Glad to say, I got my QMod'd Bushnells back. They certainly haven't disappointed and work very well. My only gripe again, is the fully coated coatings instead of fully multicoated coatings. Maybe one day I'll pay Siebert some extra dough to produce me a custom pair of fully multicoated eyepieces to upgrade the QMod's.
Heh...I'm looking forward to your review as well.