Agreed.  I am converting my machines to 4U cases, but it is a slow process (looking for deals) and I am glad I went for the GPUs first before trying to put them into enclosures.

On that note, I love 1U servers (for space), but they can be difficult and expensive to service if something goes wrong.  2U/3U/4U is more cost-effective and you will have more options.

Edit: $2k per 1U for the Tyan?  nope.