Thanks to "snowconeman22", a commenter on a Clutch Fans forum, who brought up the following possibility concerning who the Astros still might sign from the 2012 draft. Assuming Tyler Heineman signed for his slotted value of $140,400 and the Astros can sign Nolan Fontana and Preston Tucker for a combined total of $700,000, they would set up the following scenario concerning 11th Round Pick Hunter Virant:
They could offer Virant the $100,000 allowable bonus + about $650,000 extra for a total offer of approximately $750,000. At this amount, the Astros would avoid the loss of a draft pick in the 2013 draft. They would also be able to offer mid-second round money to Virant, LHP, a UCLA committment.
NOTE: Minutes after posting this, I see that Fontana has signed for $875,000, rendering this post a pipe dream. It was fun while it lasted.