New fork for Cannondale Trail SL

I want to upgrade the fork on my partners Cannondale Trail SL and have hit a few snags. The current fork has a 1.5 steerer and 9mm QR - this seems to be VERY rare (non-existent?) on any decent-ish fork. So I'm after recommendations for what option to go with (they seem to me to be):
1- Get a new 1.5 fork with whatever axle it comes with and get a new front wheel to match.
2- Get a new 1-1/8 fork with 9mmQR and upgrade the headset to match.
3- Get my head around what spacers I might need to run a 1-1/8 fork (or tapered) in the current headset. This seems the most sensible option, other than the fact that finding the right spacer(s) seems to be impossible.
It seems as though Cannondale have made a great frame, made it a bike for cheap, and suckered me into thinking it would be easy to upgrade, while actually making it incredibly bloody difficult! Unless I'm missing something, which is possible, I just don't see how it's possible to do the sensible (cheap) option to upgrade the forks. *sigh*
Thanks for any help you can give!
1- Get a new 1.5 fork with whatever axle it comes with and get a new front wheel to match.
2- Get a new 1-1/8 fork with 9mmQR and upgrade the headset to match.
3- Get my head around what spacers I might need to run a 1-1/8 fork (or tapered) in the current headset. This seems the most sensible option, other than the fact that finding the right spacer(s) seems to be impossible.
It seems as though Cannondale have made a great frame, made it a bike for cheap, and suckered me into thinking it would be easy to upgrade, while actually making it incredibly bloody difficult! Unless I'm missing something, which is possible, I just don't see how it's possible to do the sensible (cheap) option to upgrade the forks. *sigh*
Thanks for any help you can give!
Pffff. Never thought I would feel this lost as regards bike tech 

0
Posts
As I'm a long time Marzocchi fan (the plushness!), and my partner is a fan of the colour scheme. Also it seems more sensible to get a new headset than new wheel. My only questions then are:
How hard is it to change an integrated (or semi integrated?) headset? I'm happy to swap standard 1-1/8s around all day long, just never had integrated ones before!
And what headset would I actually need? I've Got my head in a spin trying to catch up with all the different types available!
Get some C'Dale to 1 1/8 headset reducers. And a 1 1/8 headset and fit the fork.
Or just a suitable headset.
Parktools :?:SheldonBrown
http://www.cannondalespares.com/Cannond ... il/3-40375
Which is what I need - I think it's actually a standard 1.5 headtube in the SL3, except for being 'semi-integrated'. So I'll get the 'Zocchis and that headset and try my best to report back on how the process - just in case anyone else is interested! (I've obviously been struggling to find info on this myself...)