I purchased the F-15EX throttle combo on launch day, approx 45-1hr into the sale (order was confirmed and stated in progress). Still have not shipped yet. Opened a support ticket, and their response is "Sorry, the stock is temporarily short, we are producing and will replenish soon."
After I pressed them on providing some sort of monetary compensation for their screw up(Wednesday this week will be 4 weeks since purchase), ie free shipping, something along those lines....Their response was...
"Dear customer, if you don't wait so long, please cancel the order, we are sorry for the inconveneince."
I have had good luck with other orders from them, but this one specifically for the F-15EX stuff is an absolute mess on their end.
One thing you might consider is getting the combo with the F-18 grips, then just ordering only the F-15E/EX grips when they finally have more. (but that is personal preference on if you want to go that route or not) I just won't be holding your breath for the F-15EX stuff to be regularly back in stock anytime soon...but could be wrong.