Richard Morrison, who ran an excellent campaign against Tom Delay in 2004 (I met him at Democracyfest '05 in Austin and he's a great guy), has started a campaign to draft State Rep. Rick Noriega for the U.S. Senate race against John Cornyn in 2008. Morrison argues that Noriega would be a strong candidate because he is a veteran (you can watch him being given the oath of office by his military mates in Kabul, Afghanistan while the Texas House meets during the first day of its session at his website here and read his Afghan journal here), a Hispanic, and a proven legislator. He is also from a safe Democratic district in Houston, so Texas Dems wouldn't run the risk of losing a State House seat should he decide to run.
I want to wait and see who else might get in, but I agree that Noriega would at least be a credible candidate who could excite the Democratic base (and potentially the growing Hispanic population in Texas) and make this race competitive. However, if he really is thinking of running, it would be wisest for him to get in the race soon so he can start raising awareness and precious fundraising needed to mount a good campaign against Cornyn. The failure to do either in past elections is what has doomed our statewide candidates to certain defeat.
With that in mind, ActBlue is building a nest egg for whomever is the eventual nominee.