The Wildcat is my favorite WW2 plane!
I love the Guillow 500 series and appreciate how remarkable it is to still have $12 kits available. But I'm not hopeful that Guillow will be adding the Wildcat anytime soon.
There is a an Earl Stahl plan for a Wildcat about the same size as the 500 series. See
http://www.theplanpage.com/esp/wcat.htm. I have not built this one. You will have to be a little creative with the plans because when you reconstruct the plan sheet from the 4 tif files, you will find that the left half of the fuselage doesn't quite match up with the right half. I guess who ever scanned it didn't ensure the segments were scanned at the exact same scale. Or maybe the original plans were not actually perfect (no CAD software back then). However, I haven't found a better plan for a Wildcat (I like the 16"-18" wingspan size models).
You can also get a 500 series sized Wildcat from Dumas, but it is more like $20-25. I have not built that one yet either.
When I was a kid, I never heard of Dumas kits so they don't have the nostalgia appeal that Guillow kits have for me. Most of what I built then was 100 and 500 series kits. I hope Guillow continues to offer the 500 series.
I worry about the decline thymekiller describes in these kits. I can't explain why I enjoyed them so much when I was a kid. I was never very good at building or flying them (still not).
I'm afraid the kits are designed for an audience that isn't a good fit for today's kids. Woodworking and propeller airplanes are not as mainstream as they were 30 or 50 years ago. Still my kids (9 and 14) do get excited when I finish a model and we go out to fly it.
This BBS and all the other internet resources may help keep the hobby going. If baseball can adapt to the 21st century, I think balsa and tissue modeling can too.