Rockstar party problems!

Oh the headache. This rockstar party is challenging me!

So, the kid is popular, he just got home from his 9th, yes 9th, party this year. It is only June! Therefore, we are looking at an invite list that may require us hiring Rod Laver Arena to accommodate. Our house is wee. Very small. It just fit 8 kids his last party. Realistically, this year will be minimum 12-15 kids, and we just won't fit them, plus any parents who wish to stay, in our house. This in itself disappoints the small man, but what to do!? Parent politics come into this! So I look at a play centre, which is okay... but then the Green Day/rockstar theme is going to be severely diluted, possibly lost altogether. This would also disappoint. So we can half arsed do the rockstar thing at a play centre...

Argh. WHAT to do!? His father seems to think that its all quite acceptable to spend upwards of $700 on a 6th birthday, but to me thats insane. Last year it was a touch less, this includes present and party. (This year we were thinking Nintendo DS and games for the present). The real problem is where how and at what cost do we do this? Less kids does not seem possible. Other venues up the cost a whack and make the theming harder.

Oh please party fairies please wave a wand and solve all my problems here, I am SO not party oriented. Should ask todays lot who held theirs at swisho posh home and included a visit from a real fire engine to complete their fireman theme... Maybe I could ask Green Day to pop along and do a number or two? Sigh...

HELP please?!?!!?