It always was possible to use C++ if you were happy to dick around with makefiles, I even think you could still use the IDE, but that was too much like hard work for me so I use the LPCXpresso environment and dev boards, really simple almost turnkey operation.
I haven't looked at the LPC range for a while, I just noticed the new LPC11U68, what a great chip and there's a Xpresso dev board for it with Arduino headers.
I may revisit my LARD framework with a view to converting to C++ and getting it running on this and also smaller chips like the LPC1114FN28 you mentioned Chris. It's a bit heavy on resources though, dunno if it will fit, I'll check out that chip now.
Meanwhile I'm grabbing the latest LPCXpresso IDE.
Rob