I would expect the answer to be no, as the front-end underwent a big transformation in V6 (as I understand it) which enabled things like Dynamic interactivity. My uneducated guess is that it is this type of functionality that is crushing your 5.2 FE.

I'm sure you could get something like that to work. Depending how gung-ho you are you can also set up a ChannelObject listener on your desktop where you can pass it arbitrary code to execute then link to that in a sandboxed cloud notebook. Thus bypassing paying for cloud credits and still being able to use a nicer FE than 5.2 would give you. Obviously there are difficulties here: what happens when you kill your desktop kernel being the chief one among them. But assuming you can get a CLI kernel link via ssh (100% should be possible) you can revive that channel interface.

If you do develop a package like that (it'd be max 500 LOC to get a simple one up and running, I'd guess) please do post about it. I'm sure lots of people would want to hear about it.