I second pretty much all of what Grodog says - except that I did find Beyond Countless Doorways to be very useful. He's right, though, in that it's not hugely Moorcockian, more a collection of cool demiplanes. There is some neat MM-style stuff in there on planar paragons, akin to the Champions of Law/Chaos, though.
The Greenwood article is top-notch - highly recommended if you can track down a copy. There is an old adventure for the Stormbringer rpg called Rogue Mistress that features some more MM-inspired plane-hopping, which is pretty cool.
In addition to the writings that Grodog mentions, you might also want to see if you can get hold a copy of the Michael Moorcock's Multiverse graphic novel. It's pretty baroque in places, but has some great depictions of multiversal travel and conjunctions between different realities, and acts as a good companion to the Blood novel.
You could easily take some of the Planescape material and break it away from the Great Wheel cosmology and devise a more MM-style set of planes with that. The various planar towns and settlements, plus a bunch of the planar sites, can be ripped out and inserted into a MM cosmology without too much work.
The githyanki Incursion scenario is really good, but as pawsplay suggests, you might get better results if you customise things to your own designs and desires. You might also get some use out of Gygax' Hall of Many Panes - I've only skimmed my copy, though, so I'll let someone more knowledgeable chime in on that one if they are so inclined.
