I have some trimmings of Rotala Rotundifolia that I can offer. I originally bought this from April's Aquarium (it's Tropica brand) for my 10 gallon tank (low tech). I recently started up a 20 gallon tank the other week and split the plants up, so I do not have much to spare at the moment. I can provide you with approximately 4 stems, that around around 3" tall, which should give you a decent start with this plant.
Let me know if you are interested. Wouldn't mind if you had a few trimmings of some other plant that we can maybe trade (anything, even small bits like Christmas moss). If not, no worries as you can still have these trimmings without anything to trade.