Since you're looking for a pack for you, you might get more varied answers in the lightweight gear section. You might ask one of the mods (or rather, one of the more experienced mods, unfortunately not including me ) to move this thread for you.

I think you're the person I answered on BPL, but I'll repeat the info here for this audience. My son takes surfing gear with him, especially his heavy and bulky wet suit, on our family backpacks to Washington's Olympic coast, so he has an 85 L Osprey Atmos. Without the wet suit, he wouldn't need such a big and heavy pack. I've been able to take one grandkid at a time for 3 days using my usual 40L Six Moon Designs Comet (now discontinued), without even having to use the extension collar. That includes one pad and sleeping bag (2.5 lbs. TNF Tigger) for the youngest kid and a Tarptent Squall 2 (34 oz.) as well as food for both of us--total pack weight for me about 25 lbs. The 6-year-old carries his own clothing (including a complete change of clothes for the inevitable getting wet), snacks, water bottle and small toy in a day pack that has a hip belt (total pack weight 5 1/2 lbs.). The two older kids (now 9 and 11) also carry their own sleeping bags and pads, and the oldest now carries several pounds of community gear (not much lighter for me because he eats more!)

It really depends on how heavy and bulky your combined gear is. If you have the rest of your and your child's gear, try stuffing it and the equivalent in weight and bulk of 3 days' food into a measured container to see how much space it takes up. (For "quick and dirty" calculation, 1 liter is about 60 cubic inches.) Then weigh the total. That will give you a good idea of what size pack you need and what weight its suspension needs to be able to support--you will find both specifications on the pack manufacturers' websites. You may find, as I have, that you don't need a bomber pack at all but can use your current one. If you do need something more, check out the websites for both mainline packs (Osprey, Deuter, etc.) and the beefier "cottage industry" packs such as ULA-Equipment for those specifications (size and weight supported). However, please note that pack fit is almost as individual as shoe fit, so what fits your specs or works for others may turn out to be highly uncomfortable for you, just as many size 10B shoes don't work for me even though that's the size I normally wear. You may have to wait until you return home, box up your gear and take it shopping with you.

In another 2 years, your older child should be able to carry her own sleeping bag and pad in addition to her clothing, snacks and water, so unless you plan to take the younger one out sooner than that, you shouldn't need to carry more than one kid's sleeping bag. If you're taking the boy out sooner, though, you will need room for 2 sleeping bags. If you don't have one for the boy yet, I recommend the TNF Tigger, which is about a pound lighter than the one you have for the girl but is very warm (approximately 20* F) and surprisingly durable (my grandkids' bags have been through many launderings without significant loss of loft).