I like the notion of making the table adjustable in length for convenience of moving, etc. I'm in an old farmhouse and have purchased 2 solid wood dropleaf tables. The are 14- 16" each with the leaves down. When I have a large gathering or need to sew I flip up the wings and slide them together. The total for the 2 tables was $85- found on Craigslist and Freecycle. Instead of a dropleaf you could salvage the expansion hardware and trestle legs from an old dining room table. Construct your table so you can add a leaf or two when you need the longer length. Using bookcases or filing cabinets as proposed above for the base of your table will give great storage options. Also check out free workbench plans on the internet. Rounding the tabletop corners slightly will avoid fabric snags and bruises.