Ok, so I have these Celstion 30watt 8 ohm speakers, and some 235watt 8 ohm Nipponamerica speakers.......the NA are supposed to be "darker sounding" speakers......I already know that I can't put 4 of them together in one cab, because I can't push the voice coils enough with my VS100H head.......

But, what if I put 2 of them together with 2 of the 30watt Celestions in an "X" pattern? That's 530watts as compared to 940watts compared to 120watts.....since they are all 8 ohm, does mixing the wattage matter any?
I think the only concern with mixing those speakers would be your Nipponamericas drowning out your Celestions...
They won't really be any louder... There shouldn't be an issue. There will be virtually no speaker breakup on the NA ones due to their high wattage rating, but they should be fine.
So.....should I even bother putting them in? If it's not going to help then there's really no point, yes? Also, I'm putting in a bid on ebay for another set of the Celestion 30's. I'm also looking into getting a Randall RH200 amp head to replace my Marshall VS100H.
If you can't move the speakers, there's really no point in using them. Use your Celestions, and use the Nippo-whatsits in a concert situation.
Yeah are they even guitar speakers? I don't think so..

The cab would still only be 120 W because, AFAIK, when you mix speakers, it spreads the load equally, so you still can't put in any more than 4xthe lowest wattage rating.

Does that make sense?

For a 4x12 if the lowest rated speaker was 10W and the others are 200W, you can only put in 40W max because when it spreads the load equally, even if you have 3 more 200W speakers, the 10W speaker will get way overpowered and die. Then your cab is screwed, you'll have to replace the speaker.

That's what I've been led to understand anyway, someone please correct me if I'm wrong.
Yeah....that sorta makes sense.....I bought them as guitar speakers from Shred Muzic. They said they were, "Darker" than most speakers.......but all 4 of them works up to like 940watts........I was thinking that I could at least use 2 in each cab......but then again, if there are only 2 30watt speakers in the cab, then they'll only go as high as the 30's........so it wouldn't make any difference. Good thing they weren't THAT expensive.........oil well.......if I can't sell 'em, then they'll work for monitors......yes?