Long time lurker and tire kicker, new poster

Little background on us, is we are both in our early thirties, live and work in Northern VA(dc metro area is very expensive) and have a very solid income. We are not under the IRA and Roth ira contribution/deduction thresholds, if that influences anyone's suggestions.
My proposed breakdown for implementing my piece is:
- 84,000 in the IRA - 26000 each in Bonds(split between some TLT for easy rebalancing and mostly buying bonds direct), Stocks aka VTSAX, and gold(IAU). 6000 remaining for Cash, doing a 1-3 year bond ladder(though might go lazy route and just do SHY).
15k in Ibonds
5,000 in physical gold coins
15,000 in checking and savings(liquid portion of my emergency fund for ~3-5 months of living expenses for job loss or large medical/car repairs). Will shift a third of this to a other assets in December once some of my Ibonds are 12 months old and liquid.
10,000 in Fidelity brokerage(50/50 split between LT bonds, and stocks)
This puts us slightly cash heavy on our contributions for the next 3 years, but according to my spreadsheet, we wont reach a rebalancing threshold of 35% cash weighting until 2015. that allows us to cash out a lot of the i and e bonds as we need them for down payments, closing costs, and the slew of other costs that will hit over our first year of home ownership, and worst case drop down to a 15-20% cash allocation during that year. Using the PP approach for all of our assets also protects us against inflation during that time, versus all savings or CD's.
I debated on keeping long term bonds and stocks out of taxable, but decided the extra flexibility for our multitude of accounts, plus allowing us to take advantage of profits in either the retirement of the taxable accounts as needed. With that goal in mind, any suggestions or tweaks to our approach would be appreciated.
For the Fidelity account, does anyone know if TLT offers tax advantages over the bond ladder? I have been reading conflicting info, and am not sure either way. VTI seemed to be my best choice on taxable stock options even with having to pay a brokerage fee to buy it through fidelity.
Any other suggestions, comments, or tweaks will not go amiss

thanks!
Kyle