Mine just arrived and I've done a bit of research. I was initially afraid mine woud be action figure scale like some of the ones I saw on ebay, but it's actually much closer to 28mm. Probably in the neighborhood of 1/48 to 1/40 or so. Not my pic, but here's what it looks like without the roof.
This vehicle appears to be available in at least 3 sizes. The one I have is the medium-sized "Starspeeder 3000".
The newer, larger action figure sized verison (with red paint) is the "Starspeeder 1000" which is identifiable by having 5 sets of opening doors rather than 3.
Just to confuse matters, there also seems to be a medium sized Starspeeder 3000, which is almost identical (but not quite) and in different colors.
Interestingly there's also very small versions of the 1000 and 3000 in at least 5 different paint schemes that would probably be spot-on for 15mm miniatures. I grabbed the picture below of the mini version from another blog. The figure in the pic is a 1/72 astronaut.
As for the one I have, Medium sized Starspeeder 3000...
I didn't realize all this till after I bid, but I'm very glad to have gotten the medium-sized 3000. The 3 doors on each side open via buttons on the back that also turns on some the interior lights. A separate button for each side of doors. Another button activates some sound effects and the lights at the end of the laser cannon and on mine, the 4th button appears to be broken.
It has 4 rows of seats, but I think I'll remove the last two to make space for cargo/minis/etc. Anyhow, all 3 scales of this vehicle look great. It's a nice generic shape, making it suitable for most any sci-fi setting. If anyone has the chance to pick one of these up at a reasonable price, I highly recommend it. Now I just have to decide whether to repaint and how to make a roof to replace the missing roof on mine.
Lastly, since I haven't seen any pics-for-scale with 28mm figs, here's a picture of the large action figure sized 1000 next to the medium near-28mm-sized 3000, to help you judge size.