Riskarb is right -
The gamma (i.e. the rate of change of delta, and the relative lack of it, at least early on, in the leaps calls) can really hurt you if the underlying price goes up (unlike in a standard covered call), and you can also get hurt if the underlying price goes down too much, (like in a standard covered call). As the price goes up, the short will lose more and faster, than the long can cover, until the price gets much higher. To help off set this, in putting this kind of combo trade on, if you do, try and match the options so that, relatively speaking, the volatility 'skew' is high (i.e. the implied volatility of the long option is lower than that of the short option). And, correct that, like a standard covered write (buy stock - sell call), it has a risk profile like that of just selling a naked put, especially the more in the money the long call is (the less so then the risk profile gets to look more like a curved bull call spread, or a tilted calendar spread.
With a standard covered call, the downside risk is the entire value of the underlying, less the premium of the call sold, and the there is no upside risk, except opportunity cost because you have capped your upside potential in having sold a call against your long. On the leaps covered call, there is also the risk of entire loss of the long option (the leap) if the underlying plummets, but there is also, unlike the standard covered call, theoretically unlimited risk if the underlying price rockets skyward (the upside loss rate does diminish as the price goes higher though, since the gamma of long will eventually catch up with the gamma of the short as the underlying price gets farther away from the two strike prices).
Some Alternatives (all of which have different risk profiles) to consider :
1. If there is more bullish risk in the position then buy in the money leap (not at or out of money), sell out of the money nearer term call (not at the money). This is analogous to standard bull call spread (buy lower strike call sell higher strike call) but with diagonalized (options in different months) the deeper in the money on the leap, the more the leap acts like the underlying, opening or improving your upside potential. The net negative Gamma for the position is greater than if the long were closer to at the money (gamma for all options is highest at the money and is less the farther away from at the money). However, the downside risk is still very high, because like in a covered call, the risk can still be the entire cost of the long if the underlying's price plummets. The profile gets to look more like a standard short naked put, the deeper in the money the long is.
2. Ratio it: buy more lower same strike leaps than you sell, rather than 1:1. This then becomes a calendarized (or 'time') call ratio backspread. Careful though, since net buying, do so during time when historically speaking the implied volatility of the longs is low. Otherwise, like a long straddle, profits will sag if (and loss may mount) as implied volatility goes lower, especially if the underlying price does not change. Even the expiration curve will be affected as volatility changes, as with all diagonalized (different strikes) time spreads.
3. Diagonally ratio it: Buy leap or in the money leap, buy out of the money higher strike nearer term call, sell out of the money lower strike (but not as low as the leaps's strike) nearer term call.
Both 2 an 3 are analogous to owning stock, and instead of selling a covered call, you have a different premium selling mechanism ... a bear call spread (buy higher strike call, sell lower strike call). This caps risk to that of the bear call spread, like in a standard bear call spread. You'd like the underlying's price to be just below the strike of the short call at expiration.
I might suggest, especially if you don't have much options trading experience already, that you determine the amount of risk you are willing to accept for any one of the originally considered covered call leaps trade, then simply put on a either a same month bear call spread (premium selling spread) or bear put spread (a debit spread), equal to that risk. Otherwise, like covered calls, the strategy of simply buying leap, selling call could have intolerable risk since it can approach the same risk profile as selling a nake put (i.e. high risk).
Also, I suggest that to really see and understand this stuff better, get some option software to see the risk profiles of the different combinations of options, especially if diagonalized. Optionvue is one software to look into, and Optionetics (Plantinum site, web-based, no software to install) is another.
A picture (of risk-reward) is worth a thousand words, and makes it much easier for you to decide what and how you want to trade.
-- Sigsbee