Some of the root trainers I have are 5 to a row and 10 rows to a tray as opposed to the more regular sized 4 to a row, 8 to a tray. I find they work just brilliantly, with just enough space and compost to produce really healthy plants for later planting out. I've currently got some heritage peas germinating in some and TPS in some others, but they would work well for a variety of veggies.
This method of growing suits me and helps me manage my gardening, but perhaps is not for everyone. I wonder how similar a size your coin rolls are, as they are easy to fill with soil, I'd be tempted to use them in this manner. You could always make a little cage to support the tubes.