Also make sure that there is a "vented tile" inback of your cabinets.
Not every one I see there does. Just put in a work order to the
CAC and they'll put them behind your cabinet. This should help with the
air flow around the cabinet so the air pumped out has somewhere to go
(Or help blow into the back vents)
Otherwise, contact me as we have plenty of air in our cabinets and we
can do a cross-connect for a reasonable monthly fee. 
I've had really good luck with a very large hole underneath the cabinet and
a several hundred CFM fan at the top. Telehouse has good underfloor
pressure so the larger the hole the better for the cabinet. I haven't had
good luck putting vented tiles behind - most of our equipment vents front
to rear inside the cabinets. My routers are very happy with the large
holes though:
card inlet hotpoint exhaust
RSP(2) 18C/64F 23C/73F 21C/69F
Although after seeing the rats nest of wires in some of the cabinets I've
seen over the years it's no wonder there are hotspots - nowhere for the air
to go. 
-Geoff