Is chiffon cake strong enough for a tiered cake?? I have someone requesting a 4 tiered cake, all chiffon! Does anyone have a good recipe for chiffon cake??

You can stack any type of cake.  If you have good supports in your cake, your tiers will not have lots of weight on them.  That's the key.

I've used Gretchen's Bakery's chiffon recipes and had good success.