Soldato
Maybe you've already considered this but to be honest moving to AG instead wouldn't be that much hassle or expense compared to getting a giant 20L stock pot. Building your own boiler is very easy/cheap (£30ish). You'll almost certainly have a better time boiling the water and wort with that than a dodgy electric hob. That's certainly my experience anyhow
I think moving to AG will be a bit much tbh, from what I understand it's quite a messy business and you need a decent extraction system if you're doing it indoors? The other problem with my hob is the extractor fan is awful
Having said all that, an all in one boiler would be quite cool and that would mean i could consider using it outside I suppose instead of indoors - I'm not too worried about cost so don't mind buying one, would something like this do?
http://www.brewuk.co.uk/brupak-boiler.html