I would have to think that the Avalon shares parts from other Toyotas. There is no way that the suspension is unique to the Avalon. If I had to guess what other Toyotas the Avalon shares suspension parts with I would say:
1) 2006+ Camry XV40 (V6)
2) 2006+ ES350 XV40
Put this way these two cars are built on the same chassis, and share a huge amount of parts, look at the three engine bays and you will see how similar they are.
2006+ Avalon
2006+ Camry
2006+ ES350
So this being the case I would say that there is a good chance that the Avalon, Camry, and ES350 share suspensions. Over on the Camry boards a member was asking about camry sway bars, and another member points out that the Camry and ES share the same MEGAN part number Coil-overs.
Go to post #8 I'm sure what changes between the three are spring rates, and the valving changes also, but I'm sure that the body of the shocks are the same, and if so the mounting points should be the same also.