The Violet Showcase carries several plant stands, and as you stated, the are quite expensive. I'm including a link to a catalog of theirs' that is just about light stands. There are several 4 foot models, so they should have something to meet your needs. Any stand with 1- 2 bulb fixture per shelf will be fine. They do have some that use 4 bulbs per shelf, but I think all of those are marked as not being suitable for violets. They're for higher light plants, like some orchids. I think this is the most recent catalog, but it'd be worth double checking with them just to make sure of prices, etc.

Mark

Here is a link that might be useful: Violet Showcase light stands

You may want to save some money and buy some 4 foot shop fixtures from Home Depot or Lowes.