I would also be interesting in learning more about "at your own pace" programs (meaning no deadlines, whenever I get to it, etc). Personally, I am thinking more like certificate programs as I am enrolled in a Masters program right now.
Whenever I am finished with my weekly assignments for my Masters class, I usually study some for tech certs (right now I am studying for a Microsoft cert). The thing I like about this is that it it completely my own pace as to when I take the exam. So if I have a busy week with my university class, I can ignore my Microsoft studies for awhile or I can put it on hold if life gets busy in other ways or if I just want some extra leisure time.
So, while tech certifications basically meet this need for me, I would also be interesting in university certification programs too. Something like web design/development, or programming would be great for me as I don't have very much experience there and would love to learn more. I have noticed some interesting certificate programs but I'm believe most I have seen are not self-paced.
I would prefer regionally accredited, (it was important to me that my bachelors and masters were regionally accredited) but for a certificate program nationally accredited would probably be fine and I wouldn't automatically rule it out.