Why not go the whole hog and get the gitzo 2380?
http://www.warehouseexpress.com/?/binsandscopes/tripods/gitzo.html&GCID=S18120x002&KEYWORD=gitzo%20head&gclid=COqR5eyT2pECFQ5HQwodzhdxeA#fl
There isn't a picture on here, but I've heard good reviews of it from others, and inevitably, from others still who didn't like it? There are one or two old threads on this head and similar lightweight heads if you look back over the last couple of years. Take the weight figures given on that link with a pinch of salt! I think it's actually about 500g.
Personally I have one of these:
http://www.amazon.com/Velbon-FHD-51Q-3-Way-Fluid-Head/dp/B000HGE2L0
(weight: about 600g)I bought it on offer for £80 from Cley Spy in Norfolk a couple of years ago, which compared to the Manfrotto is a bit steep! but still cheap compared to the Gitzo (I know you said if money wasn't an object...).
Personally I quite like it, but have heard from at least 2 people on here that it has 'durability issues'. I don't carry my scope around on it, but perhaps this is the source of those problems.
To be honest, I have owned other lightweight heads, including the Manfrotto 390RC2 (c.1/2kg) and 701RC2(good, but I never got on with it), but always keep coming back to my trusty Manfrotto 128 (about 1kg, though the newest versions of this are around 7-800g).
If lightest weight is your main aim, then either the Velbon or Gitzo have to be worth a look. With a big scope like yours, then a bigger head is going to be more stable, but the ability of both of these to balance the weight with sliding plates will help with this.
Incidentally, Velbon have just introduced an even smaller version (FHD-52Q). Have a look at it on the In-Focus website. I would reckon it will be too small for a big scope, but I have no personal experience of it.
I presume you intend to have a spare centre column for your tripod, so you can easily change the heads over?
Steve