Just waiting for paypal payment to be available to pre-order.... i believe it will happen when the beta is available?

Do I have to have the previous expansion packs to be able to play Rebellion? 

Were you actually charged, or did the bank put the money on hold? Some banks will place a temporary hold on the money, even if you haven't been charged yet.

No, but you will get $10 off if you have both of them. The game itself will have all of there features but will not be required to have them.

pre-ordered the game today. I hope it comes out soon. My only complaint with the game series is that there should be a 64 bit version to stop the 2gb memory limit i can live with that though.

I was charged.

Apologies - I've updated the original post: 

(Please note that if you choose a bundle upgrade option - i.e., Rebellion with the Expansion Bundle - you will be charged immediately.)

If you don't wish to be charged yet and haven't downloaded the bundle product (i.e., Entrenchment/Diplomacy), you may contact sales@stardock.com to cancel your pre-order.

I think Multithreading would be better than a 64Bit Version but i dont think that anything like that is coming.

I dont reach the 2GB Limit on large Maps (200+ Planets) but i think all the AI Commands for managing all the Ships etc. slows down alot.

Neither is really possible at this point (64-bit or multithreading).

Bummer but thats ok, Im sure yall will fine tune the current engine even more. Have yall looked at the empire tree as a souce of low FPS/studdering/lag/slowness late game?

I love this game, and will almost definitely be buying Rebellion, but they won't be seeing a preorder from me until I get some concrete gameplay info (i.e. videos).

Allowing preorders before we've even seen the product seems a little daft.

The Empire Tree slows alot yeah but it doesnt bring me over 15 FPS in the Late Game so i think there are other Points to work on too.

Not really the option to buy.  As a Sins + Entrenchment owner, it offers me to pay $40 for Diplomacy and Rebellion.  I don't particularly want Diplomacy at this point, with Rebellion on the horizon listed as a "standalone." But apparently I can buy it for $10 and then get $10 off Rebellion.  Unless I missed something where I could click through and just choose Rebellion?

If you don't own Diplomacy or Trinity, the price for Rebellion is $39.95.  Rebellion will include all the prior Sins content.

Can we expect any optimisations to counter late game lag at all? I had hoped to have at least the AI reexamined for speed gains and modability.