I would like to have the ability to be able tell the "Schedules Transactions"
features to skip processing on predesignated dates, specifically Jan 1 and Feb 29.

I run a subscription service where customers pay in advance quarterly,
semi-annually or annually against which I charge a daily fee. As the clients
submit payment in advance, I debit an Asset account and credit a Liabilities
account under the customer's name. Each day I then debit the client's account
with a daily charge and credit an "Earned Income" Equity account. I do the
accounting daily so that I have an accurate idea where each account stands with
respect to the amount of service delivered.

For ease of accounting, I have developed a "World Calendar" style accrual
system. Each quarter is defined as exactly 91 days, each half-year is exactly
182 days and each year is exactly 364 days. I essentially ignore the extra day
(January 1) and on that day, all accounts with a balance receives essentially
"free rent." On leap years, February 29 is treated exactly the same way, so
every four years customers receive another "free rent" day.

There are quite a few advantages to this sort of reckoning this way, but the big
one being the ease in computing between dates, even on leap years.  Quarters
begin and end on the same days each year (Jan 2 - Apr 2; Apr 3 - Jul 2; Jul 3 -
Oct 1; Oct 2 - Dec 31).

In order to use GnuCash to perform the daily calcuations, I simply configure the
"Scheduled Transactions" for daily runs starting from a specific date for the
required number of days (91, 182, 364). If the account is going to be active
over the new year, I just add an extra day on the run and then credit the
customer's account with an extra day's service on his subscription. The same
applies for February 29 on leap years.

In order to make the books balance, a special "Free Days" account is created
with debits equivilent to the total amount in credits that each account
receives. Sometimes, of course, mistakes are made and either too few days are
subtracted or the customer's account is not credited with the extra day's
service to keep everything in sync with the calendar. And of course, all of this
is going on while the accounts are all being balanced at year end.

It would be sooo convenient to be able to say, "run the scheduled transactions
each day for the next 91, 182 or 364 times except on Jan 1 and Feb 29. That way,
no mistakes are made by forgetting to credit a customer's account properly or
adjust the scheduled transaction with the extra day and make sure that the "Free
Days" account has the proper amount in debits to balance all the credits that
will be added to each account on that day which will immediately be withdrawn.