I've been searching now for a few days, trying to find something that may not even exist, but I figured I would post on here since you all seem very knowledgable about travel gear in general. Brief background: Hubby and I will be in Scotland May 8-18, and hiking in various locations on Skye and in the Glencoe area from the 14-17th. I would like to buy a waterproof (NOT water resistant) BACKPACK (not dry bag), that can carry our gear (camera, paper maps, cell phones, etc) and keep it dry. Although we will be traveling in what seems to be the "driest" month in Scotland, I use that term lightly. I know there is a very good chance we will be rained on, and possibly quite heavily.
I am trying to keep the total cost at $75 (about £100) or less, but want something that will last more than a year or two. Another option for us would be to use our current well-loved backpacks, used on the plane last year on a trip to England, but they are not waterproof. I have a big fear of not using enough spray-on waterproofing, to ensure that my camera at the very least would be safe in a driving rain. I also do not want waterproofing in the form of a rain cover. We have done that in the past, and have yet to find a rain cover that will stay on in even a moderate wind.
I also would like to use said backpack as one of our personal carry-on items. We are flying British Airways and they set a limit for an underseat bag (we will also be bringing two carry-ons as well) at 16x12x6. This is roughly equivalent to some of what are labeled 30L backpacks on the market. That will work fine for us, since we don't plan on stuffing it to the brim.
The only thing I have found to date that comes close is this hybrid backpack/dry bag combo on Amazon:
https://www.amazon.com/gp/product/B075SJBP4K/ref=ask_ql_qh_dp_hza
but I don't know the size of the dry bag portion. I have put in a request for more information in that regard and am hoping to hear back soon.
Since we are in our mid-40s, we find carrying a backpack the easiest way to get around. Having said that, we would prefer a backpack that has chest and especially waist straps as well. If nothing else fits the bill, I will resign myself to bringing lots of Ziploc bags to store stuff in, which we often do anyway, but I was really hoping to find a true backpack that fits the bill, where we could toss things in and pluck them out as needed, without the added inconvenience of unzipping Ziplocs all the time.
Does this backpack actually exist? Any suggestions are welcome! TIA!