So, in true Curbly fashion, we decided to do it ourselves. Here's the video, details and links are below.
For those of you who want to try this at home, here's what we ended up buying, and some tips to get you started:
3 - 3/8"x12" Sink water line extenders ($1.70 each)
1 - Kwik-Fix Super Glue (3 pack for $0.99)
1 - All purpose silicone rubber kitchen and bath caulk ($2.59)
3 - 5 lb Neodymium magnets (super-strong!) ($2.95 at Ax-man Surplus)
Sheet metal for base plates (cheap)
1. Trim pipes to desired length using a hack saw. Make sure not to cut your girlfriend's fingers off.
2. Fill one end of each pipe with the silicone caulk to create a water-tight seal. Be patient while they dry (add some pictures to your Curbly account!)
3. Glue a magnet to the base of each pipe using super glue. Super glue + fingers = bad, be careful.
4. More patience while drying (do yoga or something).
5. The metal plates go on the table under a table cloth, the pipes secure (magically!) to the vase-bases via magnetism. Flowers and water go inside.
6. Your friends think you are magic.
Watch the first Fix-Its video!