I think it depends on the design and color you choose. Personally I think so many of the designs now definitely have potential for "timelessness"...off the top of my head:
- bow satchel
- double-zip bowler from the cruise line...
Of course, these are the bags that I've been eyeing, but I know for certain there are tons more!!!
^ ITA. Coffers, I think, is Miu Miu's bread and butter. It is a classic piece and I would recommend it to anyone considering purchasing it. I seriously love mine! BUT if you want something that is more universally considered as timeless, then I agree with linpaddy, you will have to invest in one of the 'older' brands like Chanel, or if you don't mind going broke, then Hermes. Their styles have been proven to last decades, and that's how I would define timeless.