what size keepall is heidi (from the hills) carrying?

it seems whether or not the keepall has a shoulder strap increases the price significantly....is it possible to buy one w/o a shoulder strap and then get the shoulder strap separately?

also, have people w/the 45 found it big enough for travel purposes? what can you fit into it? same question goes for 50s...i'm going on vacation and i'm super excited because it gives me an excuse (finally) to get a keepall!!!! just don't know which size! Thanks guys!