OpenStack Swift vs AWS Glacier costs

Since AWS Glacier hit the road there are some interesting discussions and blogs on comparing costs between Glacier and local solutions such as OpenStack Swift. Glacier is hard to beat if you do TCO calculations that include everything like datacenter, power, cooling & staff. For many of us these costs vary a lot dependent on things like being in a fortune 500 or in a government funded agency or residing in a location with low power and cooling costs vs LA or NYC. Some of us even have the notion of sunk costs .....

If we just look at the plain storage hardware we know for example that we can get 36 drive standard Supermicro storage servers for less than $5k and we have seen the latest and greatest 4TB Hitachi Deskstar for $239 on Google Shopping. The Hitachi Deskstar model seems to have an excellent reputation and folks who know what they are doing recommend it as well. (albeit the older 3TB version).
So we seem to be getting 144TB RAW which might roughly translate to 130TiB usable in this box and it costs ($5000+36*$239)/130TiB = $105-$115/TiB dependent on your sales tax... let's say $110/TiB. Swift needs 2-3 replicas so your actual costs would end up at $330/TB or $66/TB/Y if we assume that the whole system will run for 5 years. That's not too bad compared to Glacier which runs minimally at $120/TB/Y.
If swift sounds compelling to you, you still have to operate and support it but you can actually get tech support from a number of vendors such as www.swiftstack.com .

Amar here has another idea which I find intriguing. LTFS allows you to mount each tape drive (up to 3TB capacity each) into an individual folder on your Linux box. Just using LTFS is probably painful since you may have hundreds of small 3TB storage buckets ......but if there was a way to use Swift with LTFS this could possibly push down storage costs to under $20/TB/Y. I'd like to learn more about this.