I finally found a few minutes to test the latest PCBs for the LPC11U37/LPC1347 and I'm pretty happy with both the test HW and the code base itself. I think it's a significant improvement over any of the previous code bases posted here, and I think it should be a good starting point for projects moving forward.
Overall, I'm extremely happy with the flexibility offered by the (essentially) pin and register compatible LPC11U24, LPC11U37 and LPC1347. This trio leaves a lot of room to maneuver optimizing for flash size, performance, price or package size with almost no extra SW development effort. Making a code base that makes that as painless as possible took a bit of effort, but at least it's a one time expenditure.
I don't want to post many details until the code base is ready to go live, but I think it's all come together pretty well so far, and I hope it will be a decent starting point for a lot of people. It'll definitely make things easier here to get prototypes off the ground in days or weeks rather than weeks or months.