Weel, it's been a long time since I last looked at the Mono project (cross platform .Net) but since I now have an 8Gb Pi running a 64bit OS I thought I would give it another try.
It has come a very long way since I last gave it a look and now pretty much supports all flavours of the .Net framework. As quick test, I created a page that loads data from a csv file and then graphs it using a javascript charting library