Status update:
Implemented parallel blockchain download. For now, only headers are downloaded. Download time ~4 min, CPU-bounded (need to investigate exact cause). Works fine, but not resistant to malicious nodes.
Implemented some EC cryptography in pure Erlang. Slow, but easy to understand/verify.
Switched from OpenVZ to XEN hosting on development node (still 256 MB Ram, but now with swap). Memory usage <30 MB resident, 100 MB virtual.

Plans: download whole blocks and do actual validation. Maintain UTxO set, with rollback capability.