As mentioned in other answers, trail does affect how the bike rides. I don't necessarily agree that a higher trail number means more manoeuvrability. Most bikes have trail numbers between 60-66 these days. Much older bikes had low trail numbers between 35 and 50. There are a number of reasons for the change. One advocate of Low-Trail handling is Jan Heine, the publisher of Bicycle Quarterly.
Also, Cross Bikes have a certain geometry to allow lots of clearance for mud and big tires. Going to a straight blade that is much shorter will mean smaller tires, less than 28mm probably, and difficulties putting on fenders.
Here is a trail calculator that can be helpful:
If you know your old angles, you can figure out the new ones based on some formulas from Sheldon's website: http://sheldonbrown.com/rinard/forklengths.htm
You can usually get your current angles from the vendor website, you can figure our your new head tube angle. You can also guess! But there is also a formula:
[change in head angle] = arcsin [(old length - new length)/(wheel base)]
I wanted to do something similar on my Aurora Elite, my fork is 400mm (43mm offset) and I don't like the handling (not stable enough on long-ish rides, fatiguing) These were my calculations:
Google tells me:
arcsin((400-375)/1024) in degrees
arcsin((400 - 375) / 1024) = 1.39896174 degrees
Old HT + 1.40 = 73.4 New HT
New Rake: 50mm
Tire Diameter 686mm
Wheel Circumference 2154mm
Wheel Flop 14mm
Mechanical Trail 48m
So, how do I figure out the new wheel base? The old rake was 43, the
new is 50, so we can guess the new wheelbase will be about 7mm
longer. Not quite, probably more like 5mm. So, we might get 10mm of
extra room infront of the toe-clip, as the fender is not up at the top
of the fender currently, and it will only move a couple of mm closer
to the tire, maybe 4mm? So, a real increase of 7-8mm infront of the
toe-clip, but that will be enough to get rid of the overlap.
Now, going with a 55mm rake, takes us into completely different
Wheel Flop 12mm
Mechanical Trail 43mm
This is probably too much for a wide range of speeds, and speedy
Another factor that will change bike handling by using a shorter fork
will be a lower bottom brack and less trail, putting the bike closer
to a classic touring geometry.