Visitor Visa - B2

Looks like there is a pattern of issuing visa for 3 months! Heard many other cases recently. In this case, my mom went to the embassy alone.

Questions were simple such as:
1. When do you plan on leaving to the US?
2. What is your husband's income?
3. How many kids do you have in total?

I know that the visa expiration date does not neccessarily mean anything but the date on I-94 does. Now, she is planning on travelling just before the visa date expires. Is there a chance that the immigration officer may issue I-94 for 10-15 days.

So, what are the options of getting visa at the port of entry for 6 months? That way, I can avoid filing for an extension after coming here, which again involves documentation etc.,

I saw some info on this website requesting (letter) to the officer at the port of entry to give the visa for 6 months.

Now, my question is, did anyone else try such a thing (sending a request letter to your parents to present it at the port of entry)? How did it go? Was it smooth or were there any bad reactions? She can talk in English but first time interaction with this accent may be a problem.

Any ideas, suggestions will be very helpful. Please post any other experiences regarding this.

Thanks,
Kathi Kamaluddin!