What I understand is you want to rearrange your tasks in the Task List priority wise. So I am giving answer on my assumption. According to my assumption you did not need to create Task list dynamically. Let me know if my assumption is correct or wrong without being rude !!
So for this you can create an Event Receiver which can fire when any new item has been added and in that event you can write the code to rearrange your tasks.
The sample code for rearranging list item is as given below:
using System;
using Microsoft.SharePoint;
namespace Test
{
class ConsoleApp
{
static void Main(string[] args)
{
using (SPSite site = new SPSite("http://localhost"))
{
using (SPWeb web = site.OpenWeb())
{
// Build a query.
SPQuery query = new SPQuery();
query.Query = string.Concat(
"<Where><Eq>",
"<FieldRef Name='Status'/>",
"<Value Type='CHOICE'>Not Started</Value>",
"</Eq></Where>",
"<OrderBy>",
"<FieldRef Name='DueDate' Ascending='TRUE' />",
"<FieldRef Name=’Priority’ Ascending='TRUE' />",
"</OrderBy>");
query.ViewFields = string.Concat(
"<FieldRef Name='AssignedTo' />",
"<FieldRef Name='LinkTitle' />",
"<FieldRef Name='DueDate' />",
"<FieldRef Name='Priority' />");
query.ViewFieldsOnly = true; // Fetch only the data that we need.
// Get data from a list.
string listUrl = web.ServerRelativeUrl + "/lists/tasks";
SPList list = web.GetList(listUrl);
SPListItemCollection items = list.GetItems(query);
// Print a report header.
Console.WriteLine("{0,-25} {1,-20} {2,-25} {3}",
"Assigned To", "Task", "Due Date", "Priority");
// Print the details.
foreach (SPListItem item in items)
{
Console.WriteLine("{0,-25} {1,-20} {2,-25} {3}",
item["AssignedTo"], item["LinkTitle"], item["DueDate"], item["Priority"]);
}
}
}
Console.ReadLine();
}
}
}
The above code I found here.
Let me know your thoughts.