I knew it! Man, finding something that doesn't make you look like Pricilla the drag queen is easier said than done. I wish the manufacturers would just commit to making bags for just men and not these transgender bags.
Personally, I say screww it. If you like the bag and are comfortable with yourself, then get it.
The Tumi you linked to looks like a leather computer bag, IMO. It is a messenger bag, looks masculine enough to me. If you want something that looks feminine, turn to Vera Bradley and her thousands of floral print bags.
And BTW, I have a Men's Coach bag for my work computer. You really think these look feminine?
And this is what I carry my iPad in (only in gray. although I plan on getting the darker brown version, too):