Increase Calendar Customization Options

[#1]

I wish there was a way (either through the admin tool or by working with an Omni consultant) to customize the calendar months / years to suit any situation.

For example, our business works in "marketing periods" instead of months.  There are 13 marketing periods in a year, each containing 4 weeks (except every few years, the 13th period has 5 weeks from the carryover).  Additionally, the fiscal weeks run from Thur - Wed.  None of the custom calendar options suit the needs of my business.

Ideally, I'd like to say:

-The year starts on "mm/dd/yyyy"

-The fiscal week runs Thur - Wed

-Break down my calendar into 13 periods with 4 weeks each

-Every "x" years, the 13th period should contain an extra week

-Allow for custom labeling of the periods

[#2]

There are also some common date ranges that I feel are missing.

Last 12 weeks

Last 13 months

[#3]

This is critical for us, as our calendar runs on 5-4-4 quarters.