If you think this through, the purchase of LISK with XCR is not only the cheapest way to go, but can be the safest.
An escrow with BTC in Bter is out of the question. Cryptsy has been robbed by either a hacker or an inside job. Does anyone really trust an exchange with hundreds of BTC?
Well, assuming the LISK people simply don't want a pile of XCR and no outside investors (meaning just XCR people moving to Lisk -- which is sort of dangerous, to be honest), we'd have to trust some exchanges.
Otherwise, how would new investors buy that XCR to begin with? Or eventually trade Lisk? If you are saying we can't trust any exchanges at all, why would anyone want Lisk to begin with? Too risky to use an exchange to buy/trade it.
There is an exchange that I trust. Coinbase. I have been using them for three years now. The one thing that stands out at Coinbase, is that they dont engage in fractional reserve BTC banking, and they do not use your BTC for operations. They do move the BTC deposits to an offline vault immediately, but in your account name.
I have noticed that the small satoshi deposits I receive from faucets are the same coins that I receive when I transfer them to another BTC account. Other exchanges will merge numerous small deposits, so when I withdraw, I get one BTC with the accumulated satoshi value. At Coinbase, I get all the individual satoshi coins that were deposited over time.
Here is my coinbase account: 1JntWNTpsFUdYzqyQ5Fqy24CWK1vwfrCW5
https://blockchain.info/address/1JntWNTpsFUdYzqyQ5Fqy24CWK1vwfrCW5You can see the history for yourself.
Also at Coinbase, you can have as many BTC addresses for a single account as you desire. All BTC addresses used by an account merge the BTC into the main account, which is identified by the account holders name, not the address.
This would be an excellent way to hold the escrow in BTC.
A Coinbase account would be used, and a unique BTC address could be created for each individual investor that wished to buy LISK with BTC.
First: Investors would request this address from Max or whomever was the escrow controller.
Second: Escrow controller sends unique BTC address to investor
THird: Investor sends BTC to unique account. This can be done all at once, or a little each day.
Fourth: Investor, public, and escrow controller can monitor all funds
Fifth: Funds can be refunded to investor at any time prior to ICO.
Six: After ICO of LISK, BTC transferred to LISK dev account or according to terms agreed to by investors.