I have thought about switching to Llamas or even Burros. Llamas are way to expensive to buy and I can't justify it. Burros would be a little more economical as far as price to purchase but their tack seems more expensive. They also can't go the places my goats can which is the biggest upside to goats.
Burros and horses need a lot of water and grass every day, which limits where you can camp. Goats and llamas are happy with fireweed, marginal grass, leaves, needles, and misc forage. That really provides a lot of flexibility. And as you said, they can traverse really steep terrain.
The purchase price for llamas is expensive, but I think the total cost of ownership is lower in the long run. Here's how I think it pencils out for llamas vs goats:
Llama cost $1,000 yearling (my cheapest unregistered llama was $800, most expensive $2,000)
Llama carrying capacity 60 lbs (as Beau Baty says, "any llama can carry 60 lbs")
Packing years: 11
Hay consumption: 1 ton/year
Hay cost/ton: $320
Goat cost $200 (from a dairy breeder)
Goat carrying capacity 40 lbs
Packing years: 7
Hay consumption: 1 ton/year
Hay cost/ton: $320
You need 3 goats to carry the same weight as 2 llamas and both goats and llamas can carry a full load at age 4. Just to get these animals to packing age, you will spend:
Llama: $1000 purchase + 4 years of hay ($320*4 =$1,280) = $2,280 * 2 llamas = $4,560
Goat: $200 purchase + 4 years of hay ($320*4=$1,280) = $1,480 * 3 goats = $4,440
This assumes that one goat eats as much as one llama; in my experience, that's true for full grown goats vs full grown llama (about one flake of hay per day), but may not be true for juveniles. A two year old llama is a lot bigger than a 2 year old goat, so you may end up spending more on llama hay than goat hay in the first 4 years. Overall, I think the total cost in the first 4 years is maybe $500 more for a pair of llamas.
Cost over 10 years:
The original 3 goats will be done packing by age 11, so figure you have to start another 3 goats when your first 3 goats are age 7. By that 10th year, you will have spent:
Llama: $2,280+ 6 years of hay ($1,280*6=$7680) = $9960 * 2 llamas =
$19,920
Original 3 Goats: $1,480 + 6 years of hay ($1,280*6=$7680) = $9160 * 3 goats = $27,840
3 new starter goats: $4,440 to get them to age 4
Total goat cost: $27,480 + $4,440 =
$32,280
The goat appetite and propensity to waste hay is what ruins the financials for long term goat ownership. Even if you pay $3,200 for a weanling llama (which is really easy to find), your 10 year cost for 2 llamas is only $24,320 and those will be registered llamas from known-good bloodlines that can pack more than 60 lbs.
So, when your wife asks you why you want to spend $6,000 on a pair of llamas, tell her you're doing it to save money!
Still, you can get started with packgoats for $600 plus tack vs $2,000 plus tack for llamas and that upfront savings can be difference between owning pack stock and not.