With Treasury yields near record lows, exchange-traded fund (ETF) investors have options to satiate their hunger for high dividend payouts. By branching out to other areas of the market, investors may gain greater portfolio  diversification, along with adding on high-paying investments.

Dividend-Paying Stocks
For starters, dividend-focused ETFs provide a steady stream of income. However, U.S. dividend payers may not seem all too enticing, though there are some well-established companies with great prospects for steady dividend appreciation. International stocks, on the other hand, usually offer more lucrative payouts as compared to their U.S. counterparts.

For example, the WisdomTree International Dividend Top 100 Fund ETF (DOO) offers a yield of 4.10 percent and has an expense ratio of 0.58 percent. Some of DOO's largest country weightings include the U.K. at 19.25 percent, Australia 16.97 percent and France 11.93 percent. The SPDR S&P International Dividend ETF (DWX) provides a yield of 5.14 percent and has an expense ratio of 0.45 percent. DWX largest country weightings include Australia at 15.87 percent, the U.K. at 10.87 percent and Germany at 6.53 percent.

Master Limited Partnerships (MLPs)
MLPs undertake the storage, processing and transportation of energy. They provide the infrastructure to move oil and natural gas from point A to point B. As such, these partnerships generate cash based on the volume of the products they move, not on the actual prices of the commodities.

As a result of the MLP tax-structure, the majority of the revenue is paid out to the MLP shareholder, which explains why they offer such attractive dividends. However, potential investors should be aware of the tax consequences of holding these funds, and should consult their tax expert.

The ALPS Alerian MLP ETF (AMLP) offers a yield of 6.55 percent and has an expense ratio of 0.85 percent. The JP Morgan Alerian MLP Index ETN (AMJ) has a yield of 5.51 percent and has an expense ratio of 0.85 percent. It should be noted that ETNs are subject to the credit risk of the provider.

Preferred Stocks
While institutional investors tend to be the most prolific buyers of preferred stock, the average retail investor can gain access to this market through ETF offerings. Investors who hold preferred stocks give up their voting rights in exchange for a steady stream of dividend payouts. So far, ETFs that provide exposure to preferred stocks are heavily weighted in the financial sector. Many companies in the financial sector have issued preferred stocks as a way to seek out additional capital after the last financial flop. This asset class also has a high correlation with the broad stock markets.

Some preferred stock ETFs include the iShares S&P US Preferred Stock Fund (PFF), with a yield of 7.28 percent and an expense ratio of 0.48 percent, and the PowerShares Financial Preferred (PGF), with a yield of 7.16 percent and an expense ratio of 0.65 percent.

Corporate Bonds
Corporate bonds provide a middle ground between equities and Treasuries. They are viewed as slightly safer than stocks since bondholders receive priority over stockholders in the event of bankruptcy, and they offer higher yields than government bonds. Additionally, corporate bond ETFs are another diversifier since they don't have a perfect correlation with stocks or government bonds. Through ETFs, investors may access a basket of corporate bond ETFs, which also limits the risk and hassle that comes selecting individual company bonds.

The largest corporate bond ETF, iShares iBoxx $ Investment Grade Corporate Bond Fund (LQD), has a yield of 4.61 percent and an expense ratio of 0.15 percent. Investors who are comfortable with more risk may look at ETFs tracking corporate high-yield or "junk" bonds such as SPDR Barclays Capital High Yield Bond ETF (JNK), which has a yield of 8.03 percent and an expense ratio of 0.40 percent, or the iShares iBoxx $ High Yield Corporate Bond Fund (HYG), which has a yield of 7.75 percent and an expense ratio of 0.50 percent. HYG holds bonds with a credit rating of B1/B+, whereas the JNK fund holds slightly lower quality bonds.

It should be noted that bonds and fixed-income investments exhibit sensitivity to interest rates. While changes in interest rates may not be a problem now, interest rate hikes will affect the desirability of these types of investments, especially on yield-paying assets with long maturity dates.

Investors who are purchasing ETFs solely based on dividend yield also need to be aware that the principal values of the ETFs are subject to change. While the high yield offered by these funds may seem alluring, the funds themselves may also experience volatility. It is prudent to keep this in mind and monitor your holdings accordingly.