I think Scooter is popular enough to justify making a replica of him. If he (and Rowlf) were made, I'd have to extend my replica wish list to include him (or them).
Scooter's also making a comeback. With fairly decent sized roles in the two TV movies, plus exposure from The Muppet Show DVDs, plus the fact that he was used as part of the video menus for Season Three, I'd say Scooter is at least as valid a candidate as Rowlf, if not more so. Though Rowlf's made cameos in the years since Jim's passing, Scooter's had far more lines in productions than Rowlf has.
Yes, I vote Scooter and Rowlf. They're among my absolute favorite characters, and I think they're popular enough again to make them. Who knows? The new Muppet movie might bring them back big time.
On the poses and themes for Rowlf, you're right, Luke. He would be kinda limited. But he would look FANTASTIC alongside the others. As part of the group, he's a great choice. Otherwise, there are still a few poses that come to mind. Buying him a pair of scrubs to deck him out as Dr. Bob. And, can't you just picture him and Fozzie laughing it up together?