Transpack Trv Pro, Competition Pro, or the Edge
( they're not small, but neither is the kitchen sink)
Putting boots horizontal in a bag on the bottom makes me cringe. I don't know why. So I never use that type of bag.
I've had an older Transpack for probably seven years. No issues at all with durability. All zippers still working. It can fit a lot of stuff. Right now I've got an old wax iron and a tuning kit in there. Plus extra socks, rain gloves, extra gloves, and other stuff I don't know about. Plus the helmet with goggles and neck warmer in it. I've forgotten I had a roll of duct tape in there till rummaging. Last year I kept looking for my Boot Gloves when it got cold. Couldn't find them. In April I found them buried in the Transpack.
That wouldn't happen in the new Transpack since they added a nice gray liner to the interior. Now all those black socks, boot gloves, glove liners, etc can be seen against the gray. It's a nice and useful touch. No more black hole. Gadget freaks might think about hanging a battery led light from the side. The gray will reflect from the sides.
I recently discovered you can access the interior from the front instead of just the top. (This after years of using it!). This helps when you want to grab gloves or something from the bottom without unloading everything from the top. There is also a zippered pocket inside that hangs from the side on top to keep small items separate. Like a diamond stone , keys, hand and toe warmers. Maybe a pass. Plus a zippered pocket on the top accessible from outside. I've got tons of ski straps in that one and usually a toe warmer of the day. Underneath the top is a light mesh pocket where I've put lip balm, a tin of sun screen, name tags, and an odd fleece item that velcros to goggles and protects your nose in the cold. (haven't used it)
Where the boots stay has drain holes. The Transpack has enough room to put my shells in then cram the lace up liners upside down into the boot cuff. The tops will stick out but if you do it right you can catch the heel of the liner with the zipper for security. If I'm tired i'll just clip the liners on the outside.
Those boot containers also each have a side zipper pocket for thinnish items. I've loaded it at times with trail maps, papers, and it's a great place to store Bontex shims (gasp) because they stay flat and protected. If you ever need it, it doesn't come out all crumpled. Also old or other footbeds. (I seem to have a collection)
I've actually skied with a transpack on carrying my shoes and wearing the boots. It has both a waist belt and a chest strap which keep it stable. It is obviously not for treking, but going from one place to another at a ski area, or skiing from your car to bag storage. Waist belt, chest strap, can be stored in the back along with the shoulder straps if desired.
The pack is like a small closet. Ocd'rs should be pleased by the number of separate storage pockets to stash all those things. Others will find uses for the varous pockets for years.