Cakewalk don't make any incarnation of FLStudio, FLStudio is made by a separate company. Though from Googling, it looks like Cakewalk are distributing it maybe in the UK? Hmm.
Basically, the XXL package is THE whole shebang - you get everything you'd ever possibly need, plus more advanced video-handling facilities (which make it more like Nuendo, to an extent) though it remains a perfectly good solution for audio.
I have Producer Edition on my PC, works great. I have an inkling that FLStudio "Fruityloops" Edition might be a lower specced version of FLStudio, maybe bundled with some Cakewalk package too? I say this because FLStudio used to be called Fruity Loops before they redesigned the entire program and renamed it as FLStudio to give it a more professional image.
I'm still not entirely sure of the differences between the different packages, it may be something as superficial as a rebrand for the UK market, as the Amazon UK spec of what's included in the Cakewalk-branded package seems to have everything that the Producer edition comes with in terms of bundled Synths, plugins, support for DXi etc...