If the Texans plan on going for Blackmon or Jones (assume Green's off the board), then I don't think they can risk trading back at all in the first. Look at the teams behind them that need a WR. The Rams for sure, Jags, Patriots, Chargers and Bucs could all use some WR help. Even the Redskins at 10 may go with Jones or Blackmon, as they seem to have no help for Santana Moss.
I dunno about this WR in the 1st idea, our offense seemed to do well enough this year that I think we can wait till the 3rd-5th round to pick up one or two. I think with our new defense, we would be better off using the 1st round pick to add to the front 7 and/or trade back to get more picks to fill holes. 11th is a very good spot to use for trading back and we may be able to sell one of those WRs or QBs for a late first, second and fourth pick instead.
I like this
You can pick a S like Moore late in the 1st. Then in the 2nd draft a NT like Ellis or Fua. With the 2nd 2nd rd pick you could draft a LB like Moch or Herzlich. This represents taking the BPA and you're able to fill holes in the defense with quality players. This leaves the rest of the draft for BPA. It's a great idea. The Tough part is finding a trading partner.
K.C., Chi,N.E might make good trading partners.