In my defense, my wording was ambiguous (on purpose).
I said Bairu won't come close to the 5k record. I meant that for this year. He could possibly pull a Ritz and get down under 13:20 if he stops training for marathons to work on his speed. I don't think that's out of the question, although I do think it's unlikely. In 2010 I think he will not.
I said I think the 10k record is within his reach. But I don't think he's going to aim for a fast 10k during a marathon buildup. If he runs one in the next month or two I could see the record falling, but most likely he will be in the 28-29min range if he's in the middle of a buildup. Probably next year or the year after before he takes it down (I say he will). He was on pace for low 27:30s at Stanford last year (I think that's where it was) and lost it on the last two laps to run something in the 27:50s. With marathon training extending his endurance I don't see why he wouldn't be able to do it.
Coolsaet has a similar 10k best and with two far less than ideal buildups (and a really warm Berlin) ran 2:16. I think with a proper buildup, plus the 62 at Arizona under him, Bairu can go a couple of minutes faster than that (and so can Coolsaet). [Speaking of Arizona, Ryan Hall ran really slow compared to his usual. I think he may be looking at a very good Boston race.]
Gillis has a slightly slower 10k time than either of them and he went just under 2:14 in his debut. No reason Bairu won't be faster than that.
The half marathon record shouldn't happen during a marathon buildup, so I don't think he will get it this year unless he waits until next spring to do his first marathon. I think he will do a marathon this fall, then gear up for cross country again.
The marathon record is 2:10, and I think he'll go between 2:10 and 2:13. I don't think he'll get the record his first time out.
Anyway, all conjecture. We'll see what happens when it happens.