I'm not to sure about the "Burn on Demand" format but there are multiple shows available now on amazon.com from Nick. Doug, Rocko's Modern Life... etc.
i bought the 1st season of Doug from amazon and it's great! they use pretty high quality materials for these and they play fine in everything i've got. the only 2 things about burn on demand is that they contents get no restoration(they probably wouldn't bother with these shows) and there's no extras. the cases & discs look pretty nice and the menus work well enough. i made my own digital copies though just in case the discs ever wear out or something.
Well, we watched the first four (of thirteen) episodes of The Secret World of Alex Mack last night. Our children loved it, and my wife and I remembered it fondly. Each of the episodes seem to be a tad longer than we remember them, which is a good thing.
Thanks to Heathjack for rekindling my interest in this show, which I might otherwise have forgotten.