Well I don't know how much the older Bianchi Eros specs differed from the current version but based on the current version the 54cm Trek should be a very similar size. The seat and head tube angles are the same and the TT is 4mm shorter on the Trek which also results in the wheelbase being shorter. I could be wrong but that tells me you should be able to set up the Trek just like the Bianchi was and the should fit pretty close to the same.

That said I rode a 56cm Trek when I was test riding bikes and man did I feel cramped on it. I don't know what it is about Trek's geometry but to me anyway it felt small in TT length (which I believe was one of your comments). Thing is there was no way I should be on a 58 cm bike...so I got a different bike.

How long have you had this bike? If it is only for a short time I would think the LBS would work with you on a different bike. Oh and not to pop your bubble but Lance never rode on the Madone 5.2 style frame...if you want Lance's bike get the Madone 5.2 SL.