Socializing Kids

I'm not sure what my malfunction is as a parent but my kids have no friends. Okay, that's slightly dramatic but not too far from the truth.
In the entire year of 2011 my kids had two play dates. Both were with the same set of siblings and one of them was because I was babysitting the four boys.
My boys don't get invited to play dates, or birthday parties, they've never had a sleepover and never get any phone calls.
Lion I'm not so concerned about. The class that he's in now, the socialization just isn't there and I expect less than nothing from his classmates as far as friendships.
PJ's class though is a whole other ball of wax.  I've tried to set up play dates for him, tried to make plans but it seems no one wants to hang with him. I'm not going to chase the other parents to force my son on them but it's hard sending out an email inviting classmates over for a play date and getting nothing back from the other parent.
I'm planning his 8th birthday party now and I designed a super cool invitation, made sure it got into everyone's backpacks prior to the holiday break. I followed the invite up with a heads up email to all the parents alerting them to it and I've gotten two emails back from fellow parents. Two out of fourteen. The party is less than a week away.
This morning I sent out another email as a gentle reminder that I needed a headcount for the party and could the parents please let me know if their kids were coming.
Since I err on the side of dramatic, I'm going to drop dead if only two of his classmates show up. Seriously. I might truly faint dead away if I have 2500 sq feet of play space rented, tons of cool Star Wars stuff and two kids.
The rational side of me knows that most folks have been away and probably didn't get the email or open their kids backpacks to see the invite and they will respond tomorrow or Tuesday.
Then the little voice whispers
"But what if they don't?"
and I kick into serious crisis mode all over again.
I am planning for and expecting the worst case situation.
I'm working on my
"Don't base your self worth on how many kids came to your birthday party" speech
(even though I know, at his age that's a bunch of bullshit and he's going to remember the lack of friends for the rest of his life) and if the worst case does come true, if we have only a smattering of friends and the turnout is less than expected I'm going to pull out my for emergency only card and surprise him on Monday by pulling him out of class and taking him to the city to Alice's Tea Cup for a birthday surprise high tea.