The only bonds offered by foreign issuers that Fidelity's brokerage arm will sell you are Yankee bonds--dollar-denominated debt of foreign issuers, which will give you the feel of diversity but little else.
Yes, bonds are still valuable ballast for every long-term portfolio, but in terms of looking for where the best incremental returns are likely to be going forward, Fidelity is clearly on the record: Stocks, not bonds.
In a recent report: US Equities: Light at the End of the Tunnel, Fidelity makes the case that based on current valuations for stocks and bonds, stocks look like the far better investment.