Bit late to this, and not sure I am really qualified to be giving advice, but just in case anything helps here is what I do. My current Golden Kite project has 200 colours, 80 solid and 120 blends and I do still park.
I make a set of card organisers from cereal boxes for each project with all the solid colours (including those not used in blends) grouped separately from the blends. I cut lengths from the original skeins as required, measuring them against a piece of string cut to the length I like to stitch with to make sure blends will be the same length, and pull individual strands using the method in the blog linked by Serinde. I do use slightly shorter lengths than you have mentioned, I know it's more wasteful but less tangling and fraying of ends seems to happen. If I can see there's going to be a lot of one blend I'll make up several lengths at one time, otherwise just as needed.
I tend to thread needles for several upcoming colours at the same time and stick them in the edge of the fabric in the order I'm going to use them, so there will be a period of thread preparation then some uninterrupted stitching, then more thread prep, stitching, etc which might save a few seconds here and there. Also gets quicker as I learn symbols/colours and where they are in the cards, meaning I rarely have to look up a symbol after a while (not intentional, brain just works that way).
I don't unthread needles unless I run out, although I fully understand that you don't want to risk stray needles finding their way into various parts of cats. I know there is a needle on my floor somewhere at the moment for which I have spent a long time looking. It would take me twice as long if I unthreaded/rethreaded every time though, and I do think this is probably the single biggest time-saver for me. Allyn mentioned magnets - maybe you could find a really strong one to keep them in check (the needles, that is, not the cats)?
I start and finish on the front without using waste knots which I find much neater and easier than trying to force the needle through the back of a dense area to start/finish as I would have to do if I stitched cross-country, and quicker as no flipping is required. This was my main reason for switching to parking when I started large projects - just hated the lumps I was creating on the back and felt it gave a more even result on the front as well. I do tend to use high-count fabrics and dense stitching though, might be less of an issue with lower counts and tenting. I also don't mark my chart which may save a few seconds, but I do work in columns which helps me keep my place although probably isn't the most efficient way and runs the risk of creating vertical lines.
I use an 11"x11" Q-snap frame, haven't tried a stand mainly due to lack of space and not liking to spend money but haven't really felt the need for one yet, although I'm starting to think I might be missing something given the praise for them on here. I'm sure with your skills you can adapt something to fit the purpose, or at least build something out of cheap materials.
There is no escaping the fact that increased colours, particularly blends, slows progress whatever technique you use. At the moment I stitch all my projects full cross and on areas of single or few solid colours on my single strand projects I can manage over 200 stitches per hour, but on confetti-dense areas of blended projects like the Turquoise Sea I'm lucky to manage 100, probably nearer 60-70 in really bad areas.
I still have a love-hate relationship with blending: love the result, hate the added hassle and reduced speed, which is one reason why I have more than one project on the go - would certainly stop enjoying stitching if I worked solidly on Turquoise Sea for the next year! I have had to learn to accept a slower work-rate and remember to enjoy the process as much as the result.
That's more a description
(or essay, actually, sorry) of what I do than any helpful tips - I think anything useful has probably already been said by others. In the end, if it doesn't work for you, go back to what does.
Best of luck!
This strongly hints at the fact I should use a different type writing implement. ANATHEMA! Let me explain. I was asked to be a moderator on the 'Fountain Pen Network' because I am a bit passionate about them, love using them an have collected one or two 
