|Darksol the Painbringer|
The description for crafting Rods can be found here. It is a little vague and will lead to mixed results, meaning GM FIAT is required.
For the record, though, 1/X abilities can be improved upon by increasing the charges per day. As an example, Boots of Speed are calculated as 3 (spell level) x 10 (caster level) x 2,000 / (5 / 1), which results in the 12,000 gold price, and allows for a 10 rounds/day increase. You can alter the equation slightly, giving you double the round usage per day, resulting in 3 X 10 X 2,000 / (5 / 2). This doubles the price of the item, but allows more uses per day.
On the same vein, you can simply remove the need for charges entirely and just make it an at-will/use-activated ability that lasts up to 10 rounds at a time, and the cost becomes 60,000 gold. It could even be made into a Continuous item, which then increases the value quad-fold, into a whopping 240,000 gold. Considering that activating the item is a Free Action anyway, there's no reason to do this unless you're trying to circumvent the Nauseated condition from screwing you over, but regardless, you're still screwed.