Apparently someone has done it! Though it's not on the market yet, though. Maybe someday! I'll buy one if it's ever available!
EDIT: The Acme V-twin HT engine will likely never come out. It's actually been a few years since the original thread about it, and there's been no word about it since. Too bad, really!
A warning to those looking to mod their motorized bicycles:
Most, if not all, of the hacks and mods featured on this site were made by individual hobbyists. If you are new to working with 2-stroke bicycle engines, please by aware that there's a possibility that a mod featured on this site could seriously damage your engine. Please don't try any mod from this or any other site unless you fully understand what you are doing. The owner of this blog will not be held responsible for both material and bodily damage caused by performing a modification featured on this blog. Also remember that opening up your engine may void your warranty!