I don't know about successful, but here are a few existing ones.
Check out somebody's Regex Lab. Since yesterday, I use that all the time. I'm going to integrate it in all my WxApps.
There is also my WxBrowser, which will grow a little ;)(i'll add a toolbar, html filtering, cookies support ...) and might eventually be integrated into WxChatter, a chatterbox client soon to be (i'll finish it soon).
There is also pTkXbmEdit - a Xbm Editor written in Perl/Tk, which I use all the time to create XBitmaps. It will also be improved soon (again, I just recently improved it).
pVoice is also coming out in Wx soon.
There are a few ones soon to be released
WxChatter, which I've already mentioned.
I also wrote WxMorse, but I've yet to release it. As it stands, it converts International Morse Code to text, and vice versa. It also can "sound out" morse code. I wanna make the GUI a little bit nicer, and add an interface to allow for other morse alphabets (people should not be stuck with international).
update: here is a screenshot of my "port" (for lack of a better word) of RegexLab.jpg (ain't it pretty ;)
http://www.perltk.org/ex has a crapload of stuff i'm starting to use ;)