Target Date Mutual Funds and Tax Exposure

I'm maxing out my ability to invest in tax deferred/sheltered retirement investment sources. I'm trying to pick a diverse "one stop shop" no-brainer type of fund as a taxable individual account where I can plug a little extra money and have considered one of these "Target Date" mutual funds like
T Rowe Price Retirement 20XX. These types of funds (TRP specifically) simply own shares in a diverse range of other funds within the fund family. Does this ownership of shares in multiple "sub funds" (for a lack of better terms) expose me to greater tax liability due to the increased number of transactions that would fall under the over-arching Target Date fund? Is this a bad type of place to invest money if tax exposure is a concern?

I know that many target-date funds are not managed for tax efficiency because they are intended as a "one stop shop" for people looking to park their IRA. I'm new to the whole fund world (but not completely ignorant) and am wondering how to measure the tax efficiency of a target date fund--particularly T Rowe Price Retirement 2055--in order to determine how smart it would be to use it as a taxable investment after maxing out all other tax deferred/sheltered possibilities.

One of the best indictaors of tax efficiancy in a mutual fund is the Annual Holdings Turnover. Although the ratio may vary from year to year, this number tells you (as a percentage of holdings) how often a funds sells off/trades it's holding. For example, a fund that turns over 100% of it's assets per year would indicate a higher taxable base because that means that in any given year, it has sold 100% of it's holdings at least once. This would generate more short-term capital gains/losses (taxed at income) with each trade and a corresponding current tax obligation.

The T. Rowe 2055 has a ratio of 33%, which is quite low and indicates that it uses a primarily buy and hold approach. Since they are holding the majority of their assets (67%) for more than a year, the taxation would most likely be mostly long-term capital gains (currently 5/15%). This would indicate some degree of tax efficiency.

http://finance.yahoo.com/q/pr?s=TRRNX

Hope this helps.

And once again I am learning something new. I love this forum. Thank you for your input. I appreciate it.