The "minimum order fee" is a standard procedure/function in every german edition of online shopping system as far as I know (opensource or commercial).
If a user has a minimum order total (for example order total less then 50.00 EUR) we want to charge a "minimum order fee" (for example 5.00 EUR).

Example:

Order total = 43.50 EUR ---> add the 5.00 EUR "minimum order fee"
Order total = 121.40 EUR ---> ok. do nothing. don't add the "minimum order fee"
We want to allow customers to order under the minimum order total. But if they do it, we want to charge a fee for that. This is a standard progress in European online stores.

We have realized that we need some modifications to the taxing system to fully comply with the Swedish tax regulations. The problem occurs since we are selling products with different tax charges which means that shipping and surcharge taxes needs to be split between the various products in the order. Please see the examples below:

Background: In sweden a product could be assigned 6%, 12% or 25% tax regardless of were in Sweden you live. If you sell products that should have 6% tax the shipping and payment surcharge should also have 6% tax. The problem is when you have one order containing several products with different tax.

example order 1

Product 1 total 100 skr 25% tax (25 skr tax)
Product 2 total 100 skr 12% tax (12 skr tax)
Shipping 100 skr 12% and 25% tax 50/50 split based on product sub total (6 skr and 12,5 skr)
Surcharge 100 skr 12% and 25% tax 50/50 split based on product sub total (6 skr and 12,5 skr)
Total 473,5 skr incl tax

example order 2

Product 1 total 100 skr 25% tax (25 skr tax)
Product 2 total 100 skr 12% tax (12 skr tax)
Product 3 total 50 skr 6% tax (3 skr tax)
Shipping 100 skr 6%, 12% and 25% tax 20/40/40 split based on products sub total (1,2 skr and 4,8 skr and 10 skr tax)
Surcharge 100 skr 6%, 12% and 25% tax 20/40/40 split based on products sub total (1,2 skr and 4,8 skr and 10 skr tax)
Total 522 skr incl tax

The ideal scenario would be to extend the tax calculation formula (or tax setup) in such way that we could achieve the above but still maintain the dynamic and flexible functionality that X-Cart has today. Feel free to provide possible solutions/enhancements to the requested functionality.

You also need to consider our modifications to the cart/checkout. You also need to include an hour to remap some fields at our invoice/commission payment document.

I have some products for which I have created variants for multi-quantity purchases. For example, I might sell my widgets individually, by a pack of six or a case of 24. Customers get a discount for buying a pack and a larger discount for buying a case. I have set this up as variants as single widget, pack of 6, and case of 24 with appropriate pricing.

I did not use wholesale price functionality for additional quantities of a product because I want the discount only to apply to full packs or cases. For example, if someone orders 10, they should only get the pack price on 6. We save packing costs, etc. when customers order packs or cases. I want to encourage the guy ordering 10 to go ahead and get two packs rather than giving him an option to order 10 and get the 6 price.

What I would like to be able to do is manage the total quantity in stock (lets say I start with 10 cases (240 pieces). I'd like for this to be reduced by 1 if the customers selects the single widget variant, 6 if they select the pack and 24 if they select case. As it is now, I have allocate my inventory between the three and manually adjust it if orders are running more heavier than typical on one variant or another.

We need a mod where we can turn on or off on a product by product basis (some of our variants are typical different colors, sizes, etc. and this feature does not apply). When turned on, only one variant carries inventory and the other variants are defined as some multiple of the other one so inventory adjusts appropriately.