"Twirtterbag", instead of "mailbag", because the question comes from Twitter...though it almost sounds like an insult.
@sfhood needs to know which middle relievers are going to get holds with a low WHIP.
The answer is that there really isn't a great answer. I looked at the data over the last three years and found that very few relievers stay consistent with their hold totals from year to year. Some of this has to do with set-up guys becoming closers (i.e. Carlos Marmol), but a lot of it has to do with the general inconsistencies of relievers. Take Jeremy Affeldt for instance. In 2009, Affeldt tied for the major league lead in holds with 33 (with Matt Guerrier) and posted a 1.74 ERA with a 1.17 WHIP. This past season, Affeldt posted an ever-so-slightly better K/BB rate, but saw his ERA regress to 4.14 with a 1.60 WHIP.
Then there is the fact that bullpen roles turn over all the time, like Affeldt, who was replaced in the eighth inning in 2010 by Sergio Romo. Then there are cases like Dan Wheeler from 2008 to 2009. In 2008, Wheeler had 26 holds and a 0.99 WHIP. The next season, he posted a better K/BB rate and a 0.87 WHIP, but only got 16 holds. It's just a matter of opportunity, which is almost impossible to predict with decent accuracy.
The charts below show every reliever from 2008 through 2010 who earned 20 or more holds.
Only two relievers have had over 20 holds each season since 2008 (Matt Thornton and Matt Guerrier) and none repeated a 30-plus hold season.
The problem in general, when it comes to attempting to find holds and WHIP, is that relievers are inherently hard to project. They are subject to a very small sample size of innings and most don't pitch more than one inning at a time. There are so many variables that go into the success or failure of a reliever and numbers like saves and holds are largely a product of opportunity and not skill. Case and point: Francisco Rodriguez accumulated 62 saves in 2008 after saving 40 the season before. In 2007, Rodriguez had a better K/BB ratio. Then, in 2009, his first year with the Mets, he had only 35 saves. He threw only 1/3 inning less than he did in 2008 and had exactly the same amount of blown saves.
The best way I can find to go about targeting relievers for holds is to know each team's bullpen pecking order and look for pitchers with good, consistent, K/BB rates. Last season, not a single reliever with a K/BB rate of 4/1 or better had a WHIP over 1.10. Then look for players with low BB rates. Edward Mujica, now with the Marlins, Rafael Betancourt, Joaguin Benoit, Darren O'Day, Sergio Romo, Scott Downs and Luke Gregerson are all examples for this from 2010. But even a pitcher like Gregerson, who seems to have a lock on a setup role and posted a 0.83 WHIP in 2010, isn't without risk. He posted a 1.24 WHIP the season before. Again, small sample sizes come into play here.
Personally, I am not a fan of using holds as a category in fantasy baseball. The turnover rate is higher than that of closers and "chasing saves" can be a tough task in and of itself. At least established closers tend to get a longer leash with regards to losing their bullpen role.
In conclusion, the best way to look for relievers that will deliver holds with low WHIP rates is to look at track record and pecking order. What pitchers have a track record of good command and high strikeout numbers? Then, do those pitchers have a setup job waiting for them in 2011? The best way to approach holds on draft day is to place a low value on the category and don't reach for any particular reliever. Chances are there will be extreme turnover in the holds category and you are more likely to find multiple values via waivers/free agent wire than you will on draft day.
Or you can just get your league to get rid of the category to start with.